Fix a possible crash in range.__reversed__(). (GH-10252)

(cherry picked from commit c9a6168)

Co-authored-by: Zackery Spytz <zspytz@gmail.com>

Objects/rangeobject.c

@@ -1154,6 +1154,7 @@ range_reverse(PyObject *seq)
     it = PyObject_New(longrangeiterobject, &PyLongRangeIter_Type);
     if (it == NULL)
         return NULL;
+    it->index = it->start = it->step = NULL;
 
     /* start + (len - 1) * step */
     it->len = range->length;